1. Field of the Invention
Embodiments of the present invention generally relate to power management techniques and, more particularly, to an apparatus and method to regulate voltage for Application Specific Integrated Circuit (ASIC) power management.
2. Description of the Related Art
Application Specific Integrated Circuits (ASIC) are widely used in electronics. An ASIC is powered by a DC-DC regulator. Typically, the regulator has a fixed output voltage level that is coupled via a “rail” (i.e., power bus) to the ASIC. The ASIC operating efficiency is dependent upon the voltage level i.e., the amount of power consumed by the ASIC depends on the voltage level. If the selected fixed voltage level is above or below an optimal voltage level for the ASIC, the ASIC operates efficiently and consumes more power than necessary. On a given circuit card, such as a line card, there may be about 40 regulators and as many ASICs. As a result, an inefficient operation can result in large power consumption.
Current voltage regulation techniques that attempt to optimize the voltage level utilize Voltage Identifier (VID) bits. Such technology uses 8 parallel lines to communicate the VID bits to a regulator, or a controller for the regulator. As a result, if one or more bits are bad or corrupt, the regulator will not be able to accurately regulate the voltage. Using 8 parallel lines also occupies a substantial area on the circuit board.
In other solutions a third integrated circuit (IC) is used to fetch information from the ASIC. During ASIC fabrication, the optimal operating voltage is measured and stored as digital information in the ASIC. The stored digital information is accessed by a third IC circuit. The third IC converts the digital information to an analog DC level that is coupled to the regulator as a reference level. This solution requires a third IC that adds complexity and consumes circuit card area. The additional IC and the communications necessary to couple the IC to both the regulator and the ASIC is not capable of use on circuit cards having many ASICs. For example, a line card for a DC3 application having 40 regulator and ASIC pairs does not have the space to support 40 additional ICs.
Accordingly, there is a need in the art for method and apparatus to provide ASIC power management.